OnePlus has been doing this "community build" thing for a few months as it works to unify its Oxygen and Hydrogen ROMs. There have been several community builds, and the latest is 3.5.5. It's available for download now, if you've got a OnePlus 3 and some courage. This is still Marshmallow, though. No sign of Nougat yet.
OnePlus helpfully posted a changelog for the new build, which follows.
- Added OnePlus FileDash functionality for convenient file transfers
- Added ability to switch launcher layouts
- Integration of Google Map to share locational information in messages.
- Redesign of the phone calling UI
- Added personalized ringtone information in contact details
- Added ability to view the entire call history of the selected contact
- Introduction of the OnePlus Community App
- Increased system stability
- General bug fixes
Anyone who is already on the community builds will get this version as an OTA. If not, you can flash it via ADB sideload. OnePlus 3 owners are invited to participate, but proceed with caution. You will eventually have to wipe the device and flash back to a stock build to get official updates again.